Question

ajutatiiimaa!!!! va rooog!!!​

Answer 1

16. 78a ⋮ 5 ==> a = 0 sau 5

78a = 157x

785 = 157x ==> x = 5

5/785 = 1/157 ( A )

17. x/5 = y/10 = z/15 = k

x/5 = k ==> x = 5k

y/10 = k ==> y = 10k

z/15 = k ==> z = 15k

a) 5k + 10k + 15k = 90

30k = 90

k = 3 ==> x=15 , y=30, z=45.

b) 2×5k+3×10k+4×15k=400.

100k = 400

k = 4 ==> x=20, y=40, z=60.

18. a/3 = b/4 = c/6 = k.

a) a/3 = k ==> a=3k

b/4 = k ==> b=4k

c/6 = k ==> c=6k.

(3k)²+(4k)² = 9k + 16k = 25k = (5k)² ==> a²+b² pătrat perfect.

b) 3k + 4k + 6k = 39

13k = 39

k = 3 ==> a=9, b=12, c=18.